4 ref is a bit optimistic. I even found one trade at 3 ref, but it seems like an outlier. Most people are trying to sell this for a key, and a few of them sell. 4 ref may have been the price a few days ago, but it's now very easy to get these for a key, and many of them are unsold at that price.

4 ref

http://www.tf2outpost.com/trade/8287610 - Unsold for 4 ref

http://www.tf2outpost.com/trade/8425244 - Unsold for 4 ref

1 key

http://www.tf2outpost.com/trade/8380304 - Selling for 1 key

http://www.tf2outpost.com/trade/8416230 - Selling for 1 key

http://www.tf2outpost.com/trade/8364451 - Selling for 1 key

http://www.tf2outpost.com/trade/8391244 - Selling for 1 key

http://www.tf2outpost.com/trade/8206990 - Offer of 1 key

Dis gon b gud

http://www.tf2outpost.com/trade/8443646 - Selling for 3 ref

The last trade seems to indicate that big changes are coming.